I want to ask the question below:

In the video game Undertale, the player falls down a hole and onto a pad of large yellow flowers, which breaks their fall. So, my question is: How thick would a mattress made of flowers need to be to stop a child falling down a 200-ft deep hole from getting seriously hurt?

but I’m not sure which Stack Exchange to post it on. Should it go on Physics, Mathematics, Worldbuilding, Arqade, etc.?

  • Hmm. Sounds sorta like a physics problem though, which is why I asked
    – Alphys
    Commented Aug 25, 2022 at 15:49
  • 7
    @SurpriseDog WB.SE is not just physics-lite. This isn't really a question about building a world, even if disassociated from a source.
    – VLAZ
    Commented Aug 25, 2022 at 15:50
  • I mean, if I was good enough at physics I would just answer it myself lol
    – Alphys
    Commented Aug 25, 2022 at 15:52
  • 2
    It's similar to this question: How many pillows would you need to survive a fall from a church tower? which ironically features an "existing world" Commented Aug 25, 2022 at 15:53
  • 3
    Ah ok. But you know, just because it’s there doesn’t mean that’s the best place for it to be
    – Alphys
    Commented Aug 25, 2022 at 15:56
  • 1
    This is definitely not a worldbuilding question, and it’s about an existing world.
    – Daniel B
    Commented Aug 25, 2022 at 23:28
  • 4
    You will likely get closed if you ask in on physics.SE as well if you ask it as it is currently phrased. You will be expected to specify your problem much more thoroughly, because, as it currently is, giving a physics based answer is impossible with the few parameters you give ("a mattress made of flower" is not a sufficient characterization of your mattress. You're gonna at least need to tell us how densely you packed the flowers in it) Commented Aug 26, 2022 at 6:01
  • For Physics, it should formulated to not look like this kind of question. Commented Aug 26, 2022 at 13:49
  • It wouldn't do well on Physics.SE. It would be hard to ask it without it looking homework-like, and even if you succeeded, it'd be likely to be closed as an engineering question.
    – PM 2Ring
    Commented Aug 26, 2022 at 16:08

1 Answer 1


I review questions regularly on Worldbuilding SE (WB:SE), so I'll review your question as if it was posted before in the Worldbuilding SE's sandbox. I cannot answer reasonably for other Stack Exchange sites, however.

Can your question be asked on WB:SE?

Checking what you need for something to happen and be consistent in a world is part of worldbuilding. However, there's a hole in your question that most would fall in: Since you're referencing quite directly to Undertale's universe, people will think in all fairness you are asking only about it (third-party world questions are off-topic). Now, I would consider this world can be extracted out of the question easily since I personally know that:

  • The character who falls in the game is extremely generic on a real-world standpoint.
  • Nothing about the fall is described in details. Yes, they fall in a hole in a mountain, but how deep is the fall? At most we know they hit the ground "on their belly".
  • Nothing about the flowers is really told. Well, excepted they're yellow (as generic as one can think), and they are still rooted to the ground where the kid falls.

This makes referencing to such existing world as generic as one can be if we know the game. But most people don't know all this. Even if it was quite popular at the time, this game hasn't reached worldwide, across-all-population recognition like Mario, Minecraft or Fortnite. And because of that, they genuinely can't extract the third-party world like I did. They'll have to take Undertale's world into account, which means for them the question is about third-party worlds, i.e., is off-topic. This is further worsened by the lack of simple words like "I'd like to reproduce realistically something akin to this scene"; In its form, the question lacks some "building" worlds thoughts, so it's harder than usual to extract the third-party universe from the question.

This also creates some detail and clarity issues. Since all referenced elements are very generic and blurry, do we really have enough to answer your question? We don't know the kid's weight and size because we don't even know their age or gender. There's actually no useable average when a 4 year-old girl weighs on average ~15 kg and a 12 year old one weighs 45 kg, leaving alone all the variance within the same age1. This also determines heavily the body resistance of the kid, for instance, throwing babies in the air (even just by 50 cm) is a dangerous and unwise act, but later on children and adults can jump up and down casually such heights.

What can you do to improve the question as a Worldbuilding question?

  • I'd advise to not talk about Undertale and tell instead about a generic boy/girl falling in a flower bed. It's not very useful for the purpose of your question anyway. I bet it's the reason most people would close the question2.
  • You should definitely tells the kid's age at minimum. It's my current close reason if I was to choose.
  • To be considered more as Worldbuilding and not a general physics question, you should consider how flowers can be arranged (can they be cut or not, etc.) and just what kind of flower's you're using here. Indeed, worlds have practical, multilayered constraints beyond just physics: E.g., if flowers are rooted to the ground, how can you reach the one or two meters needed to slow the fall?

1: As a reference, here's a calculator to check a child's weight depending on gender and age. There are other studies on the topic, for instance World Health Organization or AFPA's in France 2: And... Is apparently going to be, based on the comments on your WB:SE question you posted just recently.


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